<p>Before you start to configure the web cluster for maximum performance and
robustness, it is strongly recommended that you spent some time reading the
documentation authored by the Bitrix software engineers.</p>

<p>Don't try to exploit all the possible web clustering features at once roaming
blind in the wilderness of settings. It is advised that you exercise an iterated
approach and configure your web system in steps. For example:
</p>

<ol>
<li>Read the <a href="http://www.bitrixsoft.com/download/manuals/en/webcluster_guide_en.pdf" target="_blank">web
  cluster configuration guide</a>.</li>
<li>Configure memcached by analyzing data and selecting the optimum cache size (say, 128
  MB for each memcached instance).</li> 
<li>Configure another application server.</li> 
<li>Configure content synchronization using csync (or some other software).</li> 
<li>Connect monitoring software to the second and other servers.</li>
<li>Configure the balancer and the SSL termination (if required).</li> 
<li>Configure the session distribution mode, which can be: a) shared sessions
  stored in the database, b) user private sessions distributed per IP address.
  Other scenarios are also possible</li> 
<li>Configure SQL replication. Use vertical sharding if required.</li>
 </ol>

<ul>
<li>Ensure all the developers and administrators involved have read the
  configuration guide.</li>
<li>Verify that the approved web cluster architecture matches the tasks as well
  as the accessibility and performance requirements. The number of application
  and database servers, the balancer mode, the replication mode etc. have to be
  well reasoned. It is recommended to create web cluster specifications in which
  to describe the required architecture.</li> 
 </ul>